Flashcards in Chapter 13 - Autonomic Nervous System Deck (12)
Autonomic nervous system (ANS)
Can be thought of as being automatic, self-governing, or involuntary.
• we have no conscious control over the action of the ANS.
The autonomic system can be divided into two systems:
• sympathetic nervous system
• parasympathetic nervous system
Sympathetic nervous system
Is our "alert system" that can quickly ready your body to face emergencies.
Parasympathetic nervous system
Can be thought of as your "resting and digesting" system and automatically helps to maintain the normal body functions again without your conscious effort.
• chemical substances called neurotransmitters are released at the nerve endings within these systems to transmit the nerve impulses from nerve to nerve at the synapses or from nerve to smooth muscle or glands.
Drugs that affect the function of the ANS are divided into four categories based on whether they mimic or block the response of the sympathetic and parasympathetic nervous system:
1. Adrenergics (sympathomimetics = mimic sympathetic responses)
2. Adrenergic Blockers (alpha- and beta-blockers = block sympathetic responses)
3. Cholinergics (parasympathomimetics = mimic parasympathetic responses)
4. Cholinergic Blockers (anticholinergics = block parasympathetic responses)
The sympathetic nervous system can be thought of as the emergency system used to mobilize the body for quick response and action. He words to illustrate this action are:
Fright, fight, and flight.
• Example: If someone is startled in a dark place by a sudden motion, the sympathetic nerves are automatically mobilized to prepare the body can handle the fright by flight or a fight.
Sympathetic nerves are automatically mobilized and causes these reactions:
• The blood pressure, pulse, and respiration increase to supply more oxygen to the tissues.
• the peripheral blood vessels constrict, sending more blood inward to the vital organs and skeletal muscles needed for the fight or flight action.
• the bronchioles dilate to allow for greater oxygen supply.
• the pupils dilate to allow more light to see the situation at hand.
(P. 214 and 583)
Drugs that block the alpha-1 receptors found in the smooth muscle in the bladder neck and prostate, causing them to relax.
(P. 214 and 585)
Drugs that block the action of the sympathetic nervous system.
(P. 212 or 583)
Sympathomimetic drug that mimics the action of the sympathetic nervous system.
Drugs that block the action of the parasympathetic nervous system.